The present invention relates to a method for changing the direction of an edge of a cutter mounted on a pen carriage of a cutting plotter, so as to align the edge of the cutter in the proper direction for cutting.
Conventionally, a so-called cutting plotter has been known, in which a cutter is mounted on a pen carriage and is relatively movable in the X-Y direction on a sheet placed on the recording plane.
In this plotter, the cutter mounted on the pen carriage is arranged as shown in FIG. 8. Specifically, a cutting blade 54 having a knife edge 52 directed diagonally upwardly from its cutting tip or point is supported within a holder 56 for rotation about its axial center 58. With the edge 52 of the cutter pressed against a sheet placed on a recording plane, the pen carriage with the cutter 50 is relatively moved in the X-Y direction along the sheet. During cutting of the sheet surface, the main edge 54 of the cutter rotates in the holder 56 around the axial center 58 until the edge 52 of the blade 54 is directed toward the cutting direction.
When cutting in the effective plotting area 12 (i.e. the area on the inner portion of the sheet to be used by the user) of the sheet placed on the recording plane is cut by the cutter mounted in the cutting plotter, the initial portion of the cut will not be linear (as shown in FIG. 8 by broken line 16), but will rather be along a curved line (as shown by solid line 18), assuming that the edge 52 of the blade 54 was not per chance initially aligned along the cutting direction.
The reason for this is that, when the cutting is started on the surface of the above area 12, the edge 52 of the above cutter is normally not aligned in the cutting direction. Therefore, during the initial portion of the cut by the above cutter 50, the blade 54 of the cutter is forced to rotate in the holder 56 about the axial center 58 as the cutter 50 is moved in the cutting direction, such that the edge 52 of the blade 54 is gradually turned toward the cutting direction. Because of this initial "period of alignment" of the edge 52 with the desired cutting direction, the initial portion of the cut will vary from the line along which the cut should have been made. FIG. 8 shows the example where it was desired to make a straight cut (broken line 16) in the downward direction, but because the edge 52 of the blade was not initially aligned in the cutting direction, the initial portion of the cut is undesirably curved (solid line 18).